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Bleach boosting and direct brightening by multiple xylanase treatments during peroxide bleaching of kraft pulps
Author(s) -
Wong Ken K. Y.,
Martin Lori A.,
Gama F. Miguel,
Saddler John N.,
de Jong Ed
Publication year - 1997
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19970520)54:4<312::aid-bit3>3.0.co;2-n
Subject(s) - xylanase , bleach , peroxide , kraft paper , kraft process , chemistry , lignin , pulp (tooth) , pulp and paper industry , botany , organic chemistry , enzyme , biology , medicine , pathology , engineering
The effects of multiple xylanase treatments were assessed during the peroxide bleaching of three pulps: Douglas‐fir (kraft); Western hemlock (oxygen delignified kraft); and trembling Aspen (kraft). The addition of a xylanase treatment stage, either before or after the peroxide bleaching stage(s), resulted in the enhanced brightening of all pulps. A higher brightness was achieved using two enzyme treatments, one before and one after the peroxide stage(s). Both bleach boosting and direct brightening seemed to contribute to the enhancement of the peroxide bleaching. Compared to xylanase prebleaching, xylanase posttreatment of peroxide bleached pulps solubilized less lignin and chromophores and made smaller amounts of these materials alkaline soluble. Nevertheless, the final brightness achieved by xylanase posttreatment was similar or superior to that achieved with xylanase prebleaching of the corresponding unbleached pulps. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 312–318, 1997.